Is Remove Interval easy or hard?

Remove Interval is generally considered a medium-level problem. The implementation is straightforward once you identify the three overlap cases, but handling boundary conditions correctly can be tricky. It mainly tests understanding of interval overlap logic and careful conditional checks.

Remove Interval Python/Java solution

Most implementations iterate through the interval list and append valid segments to a result list. Python uses list append operations, while Java typically uses ArrayList . The same case-based logic applies in C++ with vector and in Go with slices.

How to solve Remove Interval in O(n)?

Iterate through the interval list once and compare each interval with the removal range. If the interval is completely outside the removal interval, keep it unchanged. If it overlaps, append the remaining left portion or right portion after trimming the overlap. Each interval requires constant work, giving an overall O(n) runtime.

What is the best approach for Remove Interval?

The best approach is a case discussion method that scans the intervals once and handles overlap using boundary comparisons. For each interval, determine whether it is completely outside the removal range or partially overlaps it. Add the unaffected part(s) to the result. This runs in O(n) time with O(n) extra space.

Is Remove Interval asked at Google/Amazon/Meta?

Interval manipulation problems similar to Remove Interval appear frequently in interviews at companies like Google, Amazon, and Meta. Variants include merging intervals, inserting intervals, and interval intersection. These problems test reasoning about boundaries and efficient linear scans.

What data structure is used in Remove Interval?

The solution primarily uses arrays or lists to store intervals and build the resulting intervals after removal. The algorithm relies on simple comparisons of interval boundaries rather than advanced data structures. Understanding interval representation and iteration is the key requirement.

What is the time complexity of Remove Interval?

The optimal solution runs in O(n) time because each interval is processed exactly once. Only constant-time comparisons and append operations are performed per interval. The space complexity is O(n) in the worst case because the result list may store up to all intervals or split segments.

1272. Remove Interval - Practice Online

A set of real numbers can be represented as the union of several disjoint intervals, where each interval is in the form [a, b). A real number x is in the set if one of its intervals [a, b) contains x (i.e. a <= x < b).

You are given a sorted list of disjoint intervals intervals representing a set of real numbers as described above, where intervals[i] = [a_i, b_i] represents the interval [a_i, b_i). You are also given another interval toBeRemoved.

Return the set of real numbers with the interval toBeRemoved removed from intervals. In other words, return the set of real numbers such that every x in the set is in intervals but not in toBeRemoved. Your answer should be a sorted list of disjoint intervals as described above.

Example 1:

Input: intervals = [[0,2],[3,4],[5,7]], toBeRemoved = [1,6]
Output: [[0,1],[6,7]]

Example 2:

Input: intervals = [[0,5]], toBeRemoved = [2,3]
Output: [[0,2],[3,5]]

Example 3:

Input: intervals = [[-5,-4],[-3,-2],[1,2],[3,5],[8,9]], toBeRemoved = [-1,4]
Output: [[-5,-4],[-3,-2],[4,5],[8,9]]

Constraints:

1 <= intervals.length <= 10⁴
-10⁹ <= a_i < b_i <= 10⁹